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| author | Roland Xu <mu001999@outlook.com> | 2024-08-15 04:58:13 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2024-08-15 15:38:53 +0200 |
| commit | d33d26036a0274b472299d7dcdaa5fb34329f91b (patch) | |
| tree | 97b66051307cd6ab7a476ab9af00a00a5a1850d8 /kernel | |
| parent | Linux 6.11-rc3 (diff) | |
| download | linux-d33d26036a0274b472299d7dcdaa5fb34329f91b.tar.xz linux-d33d26036a0274b472299d7dcdaa5fb34329f91b.zip | |
rtmutex: Drop rt_mutex::wait_lock before scheduling
rt_mutex_handle_deadlock() is called with rt_mutex::wait_lock held. In the
good case it returns with the lock held and in the deadlock case it emits a
warning and goes into an endless scheduling loop with the lock held, which
triggers the 'scheduling in atomic' warning.
Unlock rt_mutex::wait_lock in the dead lock case before issuing the warning
and dropping into the schedule for ever loop.
[ tglx: Moved unlock before the WARN(), removed the pointless comment,
massaged changelog, added Fixes tag ]
Fixes: 3d5c9340d194 ("rtmutex: Handle deadlock detection smarter")
Signed-off-by: Roland Xu <mu001999@outlook.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/all/ME0P300MB063599BEF0743B8FA339C2CECC802@ME0P300MB0635.AUSP300.PROD.OUTLOOK.COM
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/locking/rtmutex.c | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c index 88d08eeb8bc0..fba1229f1de6 100644 --- a/kernel/locking/rtmutex.c +++ b/kernel/locking/rtmutex.c @@ -1644,6 +1644,7 @@ static int __sched rt_mutex_slowlock_block(struct rt_mutex_base *lock, } static void __sched rt_mutex_handle_deadlock(int res, int detect_deadlock, + struct rt_mutex_base *lock, struct rt_mutex_waiter *w) { /* @@ -1656,10 +1657,10 @@ static void __sched rt_mutex_handle_deadlock(int res, int detect_deadlock, if (build_ww_mutex() && w->ww_ctx) return; - /* - * Yell loudly and stop the task right here. - */ + raw_spin_unlock_irq(&lock->wait_lock); + WARN(1, "rtmutex deadlock detected\n"); + while (1) { set_current_state(TASK_INTERRUPTIBLE); rt_mutex_schedule(); @@ -1713,7 +1714,7 @@ static int __sched __rt_mutex_slowlock(struct rt_mutex_base *lock, } else { __set_current_state(TASK_RUNNING); remove_waiter(lock, waiter); - rt_mutex_handle_deadlock(ret, chwalk, waiter); + rt_mutex_handle_deadlock(ret, chwalk, lock, waiter); } /* |